!" #$% !#% & !" # ! " $% ! &’ " ( )# ( )# *%*$+,’+’% -". Journal of the Audio Engineering Society. ’( ) * +( &% ,(% ,! -.% & /!" ,% !(% ,) .-% &0 ,% !(% ,) .-% & /!" &% 1 )2% ,! -3% &0 A subjective listening test was conducted to determine how objectionable various amounts of latency are for performers in live monitoring scenarios. Several popular instruments were used and the results of tests with wedge monitors are compared to those with inear monitors. It is shown that the audibility of latency is dependent on both the type of instrument and monitoring environment. This experiment shows that the acceptable amount of latency can range from 42ms to possibly less than 1.4ms under certain conditions. The differences in latency perception for each instrument are discussed. It is also shown that more latency is generally acceptable for wedge monitoring setups than for inear monitors. Over the past couple decades, digital audio gear has become increasingly common in nearly every area of audio production and reinforcement. Some concern has been raised that the latency inherent in a digital system can degrade the perceived quality of the audio and even affect the musician’s ability to perform. Some of the most common sources of latency are the use of digital buffers and filters. Even the process of sampling often includes a filter, and thus introduces some delay. As the number of filters is increased, the latency also increases. Therefore, it is expected that a large number of filter taps can easily create an audible delay, which may be perceived as comb filtering or even echo in the worst cases. Theoretically, even a 50*s delay (about 10 samples @192kHz) might be audible under certain conditions. If combined acoustically with the original sound, the resulting comb filter would have a null at approximately 10kHz. (Note: this delay would be equivalent to simply placing one speaker 1.7cm behind another speaker that is playing the same sound.) For an example, take one commercial audio processor that samples at 48kHz. It uses an ADC with a group delay of 37 samples and a DAC with a group delay of 29 samples, which results in a total latency of about 1.4ms. If this is combined